Expressions have been derived which show that the charge-density susceptibility in k-space is related to quantities that appear in differential cross section formulae for inelasting scattering. For high frequencies and large momentum transfers the susceptibility can be related to a generalized Compton profile and, under the assumption of closure and for uncorrelated wave-functions, the susceptibility can be rigorously expressed in terms of static form factors. The susceptibilities are the fundamental quantities in terms of which the dispersion and polarization energies can be concisely and accurately expressed. Preliminary investigations, using closure, indicate that for interacting He atoms, the second order perturbation energy comprising dispersion and polarization energies, agrees well with experimental data. We plan to extend the treatment to other noble gas atoms, using the atomic form factors tabulated in the literature, and numerical integrations. The feasibility of evaluating susceptibilities, without the use of closure, from generalized oscillator strength obtained experimentally by inelastic scattering of electrons, will be explored. Finally, studies will be initiated of solvent effects on the forces between dissolved molecules with special emphasis on hydrogen-bonded molecular systems. Semi-empirical methods (PCILO, INDO, etc.) will first be used to determine the optimum structures in the presence of a rigidly held monolayer of solvent molecules. Later, additional solvent layers will be included and allowance be made for molecular (translational rotation etc.) motion, within the framework of the generalized susceptibility theory.